This invention relates to scintillating and wavelength shifting fibers. More specifically, it relates to the non-uniform doping of such fibers with scintillation enhancing fluors and waveshifting dyes to maximize their light yield or to reduce the occurrence of timing tails. Scintillating and waveshifting fibers are finding increasing utility in physics and medical instrumentation. Scintillating fibers as they have been developed are comprised of scintillation enhancing fluors and waveshifting dyes uniformly dissolved into an inner layer (core material), which is then surrounded by an outer layer (cladding). The cladding serves to protect the core and enables the fiber to function as an "optical pipe." The specific composition of the core and cladding materials may vary. However, for the fiber to serve as an optical pipe, the cladding must have an index of refraction which is lower than that of the core so that the light rays are retained within the fiber's core and transported along its length by a process called "total internal reflection." In a scintillating fiber, light is generated near the track of an ionizing particle, propagates to the core/cladding interface and is either captured or lost at this boundary. A common problem associated with scintillating fibers used as optical pipes is the loss of a substantial portion of the transmitted light at the core/cladding interface. Another problem is the production of "timing tails," photons transported by the optical pipe which dribble into the photodetector long after the scintillation process is complete. Minimizing such tailing is desirable for high-rate conditions because tails can cause ambiguities in the perceived time of occurrence of a signal and in the measured strength of a signal.